This invention relates to a scintillator for radiation detection and a process for producing the same.
As solid scintillator for radiation detection, there have been used organic crystal scintillators, plastic scintillators, glass scintillators, inorganic crystal scintillators such as bismuth germanate, zinc tungstate, cadmium tungstate, etc. (Hereinafter, the solid scintillators for radiation detection are referred to simply as "scintillators".) These scintillators are colorless and transparent, but when they are exposed to radiation such as X-rays, .gamma.-rays, charged particles, they emit light. The wavelength of emitted light is in the range of 355 to 520 nm. The emitted light can be received by a photomultiplier tube, photo diode, etc., and by using the light-electricity conversion, radiation can be detected or the intensity of radiation can be measured. These scintillators are used in studies relating to measuring radiation such as in medical appliances and for measuring high energy particles and the like.
The scintillators are required to have a large light output and high dimensional accuracy. Thus, in order to collect the emitted light effectively in a light receiver with a larger light output, the surface of scintillator is coated with a light reflective material. As the light reflective material, there are used barium sulfate, titanium oxide, magnesium oxide, and the like. For example, powdery barium sulfate which has a high light reflectance is mixed with an organic binder and coated on the surface of the scintillator. As the coating method, there are employed a brushing method and a spraying method. But, according to these methods, the thickness of light reflective material is deviated to cause non-ununiformity, which results in making the dimensional accuracy of the scintillator as a whole worse. Particularly when the degree of parallel is more than 50 .mu.m, it becomes difficult to install the scintillator in a device. Further, when the thickness of the light reflective material is small, there bring about many disadvantages in that it is impossible to collect the emitted light of the scintillator effectively in a light receiver, the light reflective material is easily peeled off, and the like.